Dopamine D1 Receptor Gene Dopamine D2 Receptor Gene Dopamine D3 Receptor Gene Dopamine D4 Receptor Gene Dopamine Transporter Gene Serotonin 2a Receptor Gene Serotonin Transporter Gene Mu-opiate Receptor Gene GABA –B3Receptor Gene PENK Gene Mono-Amine –Oxidase A Gene Catecholamine –Methyl-Transferase Gene Cytochrome P450 Gene

Table 1: Proposed Genetic Addiction Risk Score (GARS).